This invention relates to capacitor discharge ignition systems used with spark ignited internal combustion engines and, in particular, to an improvement over the type of ignition system disclosed in Burson U.S. Pat. No. 4,036,201 assigned to the same assignee as this application.
In the Burson patent, a capacitor discharge ignition system is disclosed wherein voltage is developed in the primary winding of the ignition transformer by changing magnetic flux. This voltage is connected to the control electrode or gate of an electronic switch means (SCR) causing the SCR to switch to its conductive state. The primary voltage thus causes the SCR to discharge the voltage stored on a capacitor through the primary winding of the ignition coil. As a result, an ignition pulse is induced in the secondary winding of the ignition coil to provide an ignition spark for the engine.
The present invention, while similar to the Burson patent, involves a tap on the secondary winding of the ignition coil which is connected to the gate of an SCR to cause the latter to be switched to a conductive state whereby voltage stored on a capacitor is discharged through the primary winding of the ignition coil to produce an ignition pulse in the secondary.
The principal object of this invention is to provide an improved capacitor discharge ignition system in which a trigger voltage is derived at least in part from the secondary winding of the ignition coil.
A further object of this invention is to provide a capacitor discharge ignition system of the above type in which the trigger voltage is derived solely from the secondary winding of the ignition coil.